Platelet collection system

ABSTRACT

A single use system and kit for producing blood platelet concentrates is described herein. In a preferred form, the kit includes a bag set in which compartments containing blood components are adjacent to separate compartments which can be inflated to express the blood components after their separation by centrifuging.

TECHNICAL FIELD OF THE INVENTION

[0001] This invention relates to processing whole blood intoplatelet-rich plasma and, more particularly, to improvements in bloodprocessing systems for generating platelet-rich plasma from autologousblood.

BACKGROUND OF THE INVENTION

[0002] The science and effectiveness of using platelet-rich plasmaderived from the patient's own blood in surgery are documented inmedical, trade and science journals. A known method for the preparationof platelets from whole blood is described in the American Associationof Blood Bank's Technical Manual, 12th Edition, 1996, at pages 700-701,Method 9.11. A system employing this method collects the patient's wholeblood into a collection unit with two integrally-attached transfercontainers. The blood is collected into the collecting container, theother two transfer containers are collapsed, and the two transfercontainers with the collecting container are subjected to a “soft spin”in a centrifuge which brings the plasma to the top of the collectingunit, leaving red cells at the bottom. In the next step, the collectingcontainer containing the blood is squeezed in a plasma extractor toforce the platelet-rich plasma into one of the transfer containersthrough a connecting tube. A fraction comprising red cells remainsbehind in the collecting container, which is then removed. Next, the twotransfer containers, the first being empty and the second containing theplasma, are subjected to a “heavy spin” in a centrifuge to concentrateplatelets at the “bottom” of the second transfer container, leaving aplatelet-poor fraction of the plasma (PPP) above the plateletconcentrate (PC) in the second transfer container. The following stepsqueezes the second transfer container to express the PPP into the firsttransfer container. The platelet concentrate (PC) is then resuspendedand collected for use. This system uses a process requiring six separatesteps, including trio centrifugal steps and two separation steps. Theterms “light spin” and “heavy spin” are defined in Table 10.5-1 at page716 of the AABB Technical Manual.

SUMMARY OF THE INVENTION

[0003] It is an object of this invention to provide a single use systemfor producing platelet concentrates (PC). Preferably, the system is inthe form of a kit including disposable components supplied sterile indisposable packaging, and having all of the components required to drawblood from the patient, prevent blood coagulation, process the sampleinto platelet concentrate, and deliver the platelet concentrate to asurgical site. It is a particular object of the invention to providesuch a system that will be useful to medical and dental practitioners,including, but not limited to, dentists, periodontists, and oral andmaxillofacial surgeons.

[0004] The invention in one of its aspects provides a bag set comprisingtwo bags joined by a tube which includes a built-in sample site at thesecond bag and has sloped top surface geometry at both bags for improvedand more efficient cell separation and collection. This new bag set maybe pre-charged with an anticoagulant. A preferred size range is 50-100ml, but the invention is not limited to any particular size range.

[0005] In another aspect of the invention, each bag consists of twocompartments, the first for the sedimentation of cellular material andthe second to serve as an inflatable device for the purpose ofexpressing supernatant liquid from the first compartment.

[0006] In still another aspect, the invention provides a bifurcatedcentrifuge bucket having two wells, into each of which one of the cellbags is placed together with an inflatable device, and a meanssuccessively to inflate each inflatable device to perform eachexpression step following the soft spin and the heavy spin, therebyeliminating the step of removing the bag set from the bucket after eachspin. In a further aspect, the invention provides means to express thesupernatant liquid from within the bucket, thereby eliminating the needto remove the bag set from the bucket after the heavy spin.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The invention is disclosed in greater detail with reference tothe accompanying drawings.

[0008]FIG. 1 illustrates a set of two bags according to the invention.

[0009]FIG. 2 shows the bag set in a bifurcated centrifuge bucket withadjacent inflatable third and fourth respective bags.

[0010]FIG. 3 illustrates the third bag being inflated.

[0011]FIG. 4 illustrates the fourth bag being inflated.

[0012]FIGS. 5a, b and c illustrate a two chamber bag.

[0013]FIG. 5a is a schematic side view of the two chamber bag.

[0014]FIG. 5b is a sectional edge view of the bag of FIG. 5a.

[0015]FIG. 5c is a top sectional view showing the tubulations whichprovide access to the bag of FIG. 5a.

[0016]FIG. 6 is a plan view of a unitary two bag set.

[0017]FIG. 7 illustrates the bag set of FIG. 6 assembled to a supportingcover for the centrifuge bucket.

[0018]FIG. 8 is an isometric view of a centrifuge bucket.

DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

[0019] FIGS. 1-4 illustrate the principles by which bags of theinvention operate. FIGS. 5-8 illustrate a preferred embodiment.

[0020] In FIG. 1, a standard needle set (not shown) may be coupled viaaccess tube 10 to a first bag 12 which is connected via a transfer tube14 to a second bag 16. A sample site is provided at an access tube 18fitted to the second bag. The top wall 13, 15 of each bag may be slopedas shown for more efficient cell separation and collection. Theprinciples on which invention operates are schematically illustrated inFIGS. 2-4.

[0021] In FIG. 2, the bag set 12, 16 is shown in a bifurcated centrifugebucket 20 having two wells 24, 26 separated by a partition 21. Each cellbag 12, 16 is in one of the respective wells 24, 26 together with athird or fourth inflatable bag 22, 28, respectively, which is notconnected to the interior of the associated cell bag. The transfer tube14 connects the interior of the two cell bags 12, 16. Each inflatablebag has an access tube 22′, 28′, respectively. Each of the access tubes,10, 18, 22′ and 28″ may be furnished with a valve 30 to control accessto the interior of the respective bags. Transfer tube 14 may also beprovided with a valve 30, as shown, to isolate the cell bags duringcentrifugation. The fourth inflatable bag 28 is shorter than itscompanion cell bag 16, so that a desired volume (e.g., about 5 ml) ofplasma concentrate will be left in bag 16 when bag 28 is inflated to adesired pressure.

[0022] In use, the first bag 12 is charged with the patient's bloodsample in preparation for the soft spin. The inflatable bags 22 and 28are not inflated. The contents of the bucket 20 are then subjected to asoft spin as described above. After the soft spin, as shown in FIG. 3, apump (not shown) or other air source is connected via the access tube22′ to the third bag 22 and the third bag is inflated, squeezing thefirst bag 12 and forcing the plasma fraction over the transfer tube 14into the second bag 16, leaving the red cell fraction behind in thefirst bag. The contents of the bucket 20 are then subjected to a heavyspin, as described above. The third bag may be left inflated duringcentrifuging of the bucket and its contents. Following the heavy spin,the contents of the second bag 16 are a pellet of platelet concentrate29 (see FIG. 4) at the bottom of the bag, and platelet-poor plasma abovethe platelet concentrate. A pump (not shown) or other air source may beattached to the access tube 28′ of the smaller fourth bag 28, and thatbag is inflated and platelet-poor plasma may be forced into the firstbag 12 via the transfer tube 14, as shown in FIG. 4. Expression iscontinued until the platelet poor plasma above the platelet concentrateis expressed into first bag 12, leaving the platelet rich plasma in thesecond bag 16. With this new arrangement of the invention, the plateletconcentrate fraction is processed into the second bag 16 without a needto remove the bags from the centrifuge bucket during the process.Further according to the invention, the platelet concentrate can beremoved from the second bag 16 via the sample site tube 18 using a knownextraction syringe.

[0023]FIGS. 5a, 5 b and 5 c illustrate a two chamber bag 40 whichcombines a collection chamber 42 and an expression chamber 44 in asingle structure. This bag 40 corresponds to bags 16 and 28 in FIGS.2-4. In the edge view shown in FIG. 5b, three sheets 52, 54 and 56 arejoined at their peripheries with a weld seam 46 (see FIG. 5a).Typically, the sheets will be of a flexible plastic. The outer sheets 52and 56 are shown expanded for clarity. In addition, for use of thecollection chamber 42 for platelet collection (e.g., bag 16 in FIG. 4),a second weld seam 48 joins the intermediate sheet 54 to the expressionchamber sheet 56 to shorten the expression chamber so as to isolate thedesired volume of platelet concentrate with the PC produced by theinvention. FIG. 5b illustrates the effect of inflating the expressionchamber 44. A similar two chamber structure 70 (see FIG. 6), without thesecond weld seam 48, is the equivalent of the first bag 12 and itsassociated expression device 22 shown in FIGS. 2-4.

[0024] As shown in FIG. 5a, tubulations 58, 64 and 68 are provided inthis integrated structure 40 for providing access to the chambers 42 and44 (FIG. 5b). The first tubulation 58 is sealed between the sheets 54and 56 defining the expression cavity 44, and provides accesscorresponding to the access tube 28′ leading into the inflatable bag 28in FIG. 2. The second tubulation 64 is sealed between the sheets 52 and54 defining the platelet collection chamber 42, and provides access fora transfer tube (e.g., tube 14 in FIG. 1). The third tubulation 68 issimilarly provided into the collection chamber, and provides accesscorresponding to the sample site tube 18 in FIG. 1. A top view, FIG. 5c,further illustrates the tubulations 58, 64 and 68, providing access toexpression cavity 44 and collection chamber 42 of FIG. 5b.

[0025]FIG. 6 shows a pair of two chamber structures 40, 70 that may bejoined by an optional bridge 80 between their respective ends that arefitted with tubulations (58, 64 and 68 for structure 40 and 58′, 64′ and68′ for structure 70) to constitute the bag set 85. The bridge may alsobe omitted. As shown, structure 40 includes platelet collection chamber42 (FIG. 5b) corresponding to bag 16 in FIGS. 2-4 (facing upward) andexpression cavity 44 (FIG. 5b) corresponding to bag 28 in FIGS. 2-4(facing downward). Structure 70 includes a collection chambercorresponding to bag 12 in FIGS. 2-4 (facing upward) and an expressioncavity (facing downward) corresponding to bag 22 in FIGS. 2-4. Thetubulations 58, 64 and 68 shown in FIG. 5 are shown in FIG. 6, with thecorresponding tubulations 58′,64′ and 68′ associated with structure 70.In use, this bag set is placed in the bifurcated bucket 20 (FIGS. 2-4),with the structure 70 corresponding to cell bag 12 in well 24, and thestructure 40 corresponding, to cell bag 16 in well 26. The optionalbridge 80 may be flexible or rigid but, in either case, it would contactpartition 21 (FIGS. 2-4) with the pairs of bags on the desired side ofthe centrifuge bucket . As shown, the bridge is flexible and may be apart of the two chamber structures. Alternatively, the bridge could be arelatively rigid plastic molded in a U-shape to fit over the partition21.

[0026] The installation of the bag set 85 in a supporting cover 89,ready for installation in a bifurcated bucket (20 in FIGS. 2-4 and 90 inFIG. 8) is shown in FIGS. 7-8. In FIG. 7, the assembled bags are shownas they would be seen if 40 and 70 of FIG. 6 were folded at the middleand viewed from the side of FIG. 6. The larger two chamber structure 70is at the right of the drawing, and the smaller two chamber structure40, used to collect the PC product, is at the left in FIG. 7. Thetubulations provided for access to the bags that contain blood or bloodproducts may be fitted with valves 84, 88. These valves have sufficientmass to require restraint against moving into the wells 24, 26 (seeFIGS. 2-4) under centrifugal force, and supporting cover 89 is providedto support and restrain them against such movement and to facilitatemaking and breaking connections to the valves.

[0027] Supporting cover 89 is shown in FIG. 8 without the two chamberstructures 40 and 70 of FIG. 7. In FIG. 8, it can be seen that thesupporting cover 89 is intended to seat on the centrifuge bucket 90. Thetwo chamber structures 40 and 70 will be inserted into the two sides ofthe centrifuge bucket, where they will be used according to theprocedure described connection with FIGS. 2-4. The centrifuge bucketwill typically be made of a plastic, which may be clear or translucentto facilitate observation of the processing of blood into its componentsas described above.

What is claimed is:
 1. A blood platelet collection system comprising (a)a centrifuge bucket for receiving two pairs of bags, said centrifugebucket having an internal wall for separating said pairs of bags; (b) afirst pair of bags for separating whole blood into the componentsplatelet-poor plasma, red cells, and platelet concentrate, said bagsbeing connected at the top with a hollow tube in communication with theinterior of said bags, permitting transfer of the concentrates of onebag to the second bag, said bags being adapted to fit within saidcentrifuge bucket on either side of said internal wall; (c) a secondpair of bags for compressing the first pair of bags of (b), each of saidsecond pair of inflatable bags being adapted to fit within saidcentrifuge bucket adjacent to one of said bags of (b).
 2. A bloodplatelet collection system of claim 1, wherein at least one of saidfirst pair of bags of (b) and one of said second pair of inflatable bagsof (c) are an integrated structure, each such structure having a firstinterior volume for containing whole blood and the components of (b),and a second interior volume for receiving air under pressure andexpanding to compress the first interior volume.
 3. A blood plateletcollection system of claim 2, wherein said integrated structurecomprises three sheets joined with a weld seams at their peripheries. 4.A method of collecting blood platelets comprising (a) introducing wholeblood into a first expandable bag, said expandable bag being connectedto a second expandable bag by a hollow tube communicating with theinterior of each of said first and second expandable bags; (b) placingsaid first and second expandable bags into a centrifuge bucket having aninternal wall, said first and second expandable bags being disposed onopposite sides of said internal wall; (c) centrifuging said bucket toseparate the whole blood within said first bag into red cellsconcentrated at the bottom of said first bag and platelet-rich plasmaconcentrated at the top of said first bag; (d) inflating a firstinflatable bag disposed adjacent to said first expandable bag in saidcentrifuge bucket to express platelet-rich plasma into said secondexpandable bag; (e) centrifuging said bucket to separate theplatelet-rich plasma in said second expandable bag into platelet-poorplasma and platelet concentrate; (f) inflating a second inflatable bagdisposed adjacent to said second expandable bag in said centrifugebucket to express platelet-poor plasma into said first expandable bag;(g) removing said platelet concentrate from said second expandable bagthrough a sample tube having an inlet at the bottom of the bag.
 5. Amethod of claim 4, wherein said first expandable bag and said firstinflatable bag are an integrated structure, and said second expandablebag and said second inflatable bag are an integrated structure.
 6. Amethod of claim 5, wherein said integrated structure comprises threesheets joined by a weld seam at their peripheries.
 7. A compartmentedcontainer for use in separating blood into component red cells,platelet-poor plasma, and platelet concentrate comprising an integratedstructure consisting of three flexible sheets sealed at the edges toform two cavities, the first of said cavities for holding bloodcomponents and the second of said cavities for receiving air underpressure, said integrated structure having tubulations to provide accessto the interior of said cavities.
 8. A compartmented container of claim7, wherein said compartmented container is joined by a bridge to asecond compartmented container.